Presenter Information

Institution

University of Kentucky

Faculty ​Advisor/​ Mentor

Jack Leifer

Abstract

The application of gossamer (ultra-lightweight) structures to space systems has been under consideration for the past decade. Although gossamer structures offer the advantage of compact launch volume and high volume to mass ratio, their mechanical compliance makes precision control of their shape challenging, and requires good models of their dynamic behavior. One application incorporating gossamer elements currently under consideration is a precipitation radar antenna, a 25 square meter membrane with a tensioned, singly-curved parabolic structure. In order to perform its mission, the surface of this orbiting antenna must be maintained within 0.17 mm of its design profile. Tests performed on the ground and aboard the KC-135 during the summer 2003 student flight campaign on a truncated model of the precipitation radar antenna indicate that gravity, as well as membrane support conditions, play a role in the surface ripple configuration. The test was performed by precisely setting and recording the border configuration of the membrane, taking simultaneous high-resolution digital photographs of the membrane surface, and using the photos as input to photogrammetry software that automatically reconstructed the surface contour of the membrane. A follow-up flight was conducted in 2004 to obtain better quantitative data. Ideally, detailed data on how surface geometry changes as a function of membrane support conditions, tension, gravity, and material parameters will be used to verify computational models for the membrane, which will in turn be used to optimize the design of the gossamer antenna and support structure to minimize rippling.

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Rippling of Tensioned, Singly-Curved Membrane for Orbiting Precipitation Radar
in Zero- and One-g

The application of gossamer (ultra-lightweight) structures to space systems has been under consideration for the past decade. Although gossamer structures offer the advantage of compact launch volume and high volume to mass ratio, their mechanical compliance makes precision control of their shape challenging, and requires good models of their dynamic behavior. One application incorporating gossamer elements currently under consideration is a precipitation radar antenna, a 25 square meter membrane with a tensioned, singly-curved parabolic structure. In order to perform its mission, the surface of this orbiting antenna must be maintained within 0.17 mm of its design profile. Tests performed on the ground and aboard the KC-135 during the summer 2003 student flight campaign on a truncated model of the precipitation radar antenna indicate that gravity, as well as membrane support conditions, play a role in the surface ripple configuration. The test was performed by precisely setting and recording the border configuration of the membrane, taking simultaneous high-resolution digital photographs of the membrane surface, and using the photos as input to photogrammetry software that automatically reconstructed the surface contour of the membrane. A follow-up flight was conducted in 2004 to obtain better quantitative data. Ideally, detailed data on how surface geometry changes as a function of membrane support conditions, tension, gravity, and material parameters will be used to verify computational models for the membrane, which will in turn be used to optimize the design of the gossamer antenna and support structure to minimize rippling.